The invention relates to a system and method for preparing and feeding cleaned textile fibers to associated textile machinery in which a flow-through air stream conveys fibers through a cleaner with increased cleaning efficiency directly into a vertical chute feed.
In numerous processes involving textile fibers preparatory to making woven or non-woven textile fabrics, the fibers are opened, cleaned, and blended in various steps and combinations. These operations are carried out in an area of a mill commonly referred to as a "blowroom" because fibers are conveyed by an airflow caused by one or more transport blowers. In certain fiber processes it is typical to feed fibers vertically by means of a vertical chute feed. A typical vertical chute feed is disclosed in U.S. Pat. No. 4,476,611 having a batt formation chute section in which fibers fed in a column are compacted and densified into a fiber batt. The fiber batt is then discharged from the vertical chute feed to an associated machine a carding machine or other processing machine. This type of vertical chute feed typically includes a transition or reserve section on top of the formation chute section. Fibers are delivered by a fiber-laden airflow horizontally into the reserve section. The air exits the reserve section whereby fibers are deposited in a column above a top feed roll which feeds the fibers into the formation chute section. Fibers are typically cleaned and fed into the airflow air stream by a flock feeder, for example, as shown in U.S. Pat. No. 4,682,388. The fibers are fed from the flock feeder to the vertical chute feed. The flock feeder includes a pair of feeder rolls having a nip between which the fibers are fed onto an apron which delivers the fibers into the fiber-laden air stream to the reserve section of the chute. The amount of fibers fed to the transition section is determined by sensing air pressure in the supply duct leading to the reserve section. Fibers accumulate in the reserve section, the pressure increases. This is because an air exit arranged across a wall of the reserve section becomes more or less blocked with fibers so that the air pressure changes accordingly. U.S. Pat. No. 4,682,388 disclosed such a feed and control system. This change in air pressure is used to sense the quantity of fibers and control the feed rolls of the flock feeder to adjust the fiber supply accordingly. The feed roller of the cleaner provides a nip feed which can stop and start the supply of fibers in a positive manner without any time lag, i.e. the supply or nonsupply of fibers is relatively instantaneous. When the carding machines stop, the supply of fibers is stopped so that the controlled quantity of fibers in the reserve section remains relatively level and equal to that desired. Generally, a quantity of fibers is desired which corresponds to a level leaving a part of the air exit unblocked. The escape of air is necessary to prevent applying too much pressure on the fiber column in the reserve and loading down and choking of the feed roll.
Fiber cleaning machines without a nip are known wherein fibers are drawn across fiber cleaning and opening rollers solely by a flow-through airflow. A flow-through fiber cleaner is manufactured by Hergeth Hollingsworth GmbH of Duelmen, W. Germany under the designation WRZ type roller cleaner. This roller cleaner is particularly suitable for cleaning different kinds of very trashy cotton and is mainly used as a first cleaning machine within a cleaning line. Flow-through cleaners are conventionally placed between a bale opening machine and the blending station within a blowroom line. This type cleaner has very good cleaning efficiency and opening characteristics. The fiber material is drawn through a pair of rollers axially and exits the cleaning machine on the other side while all of the time being contained by the fiber-laden airflow. However, there is no nip feed in the flow-through cleaner to control and prevent excess fiber accumulation in the reserve section when it is desired to stop the feeding operation. Excess fibers contained in the airflow lines would be deposited in the reserve section which could choke the tip feed roll down. Because there is a need to feed vertical chute feeds with cleaners having nip feeds, the flow-through type cleaners have not been used to feed vertical chute feeds.
Accordingly, an important object of the invention is to provide a textile fiber preparation feed system having increased cleaning efficiency for feeding fibers to a vertical chute feed.
Another object of the invention is to provide a textile fiber preparation and feed system for feeding fibers to a vertical chute feed using a flow-through fiber cleaner which feeds fibers directly to the chute feed.
Another object of the invention is to provide a method for cleaning and feeding cleaned fibers to a vertical chute feed using a flow-through fiber cleaner having increased efficiency.
Another object of the invention is to provide a system and method for feeding cleaned fibers to a vertical chute feed by means of a flow-through cleaner without depositing excess fibers contained in the flow-through air stream into the chute feed upon ceased demand for fiber discharge from the chute.
Another object of the invention is to provide a method and system for feeding fibers to a vertical chute feed directly from a flow-through type cleaner in which control of the system is had in such a manner that excessive fibers contained in the flow-through air stream are compensated for when a carding machine fed by the chute feed is stopped to prevent choking of the chute feed roll when carding is resumed.